go-xmlsec

A partial wrapper for xmlsec.

As seems to be the case for many things in the XMLish world, the xmldsig and xmlenc standards are more complex that may be nessesary. This library is as general as I could reasonably make it with an eye towards supporting the parts of the standards that are needed to support a SAML implementation. If there are missing bits you feel you need, please raise an issue or submit a pull request.

Examples

Signing

key, _ := ioutil.ReadFile("saml.key")
doc, _ := ioutil.ReadAll(os.Stdin)
signedDoc, err := Sign(key, doc, SignatureOptions{})
os.Stdout.Write(signedDoc)

Verifying

key, _ := ioutil.ReadFile("saml.crt")
doc, _ := ioutil.ReadAll(os.Stdin)
err := xmldsig.Verify(key, doc, SignatureOptions{})
if err == xmldsig.ErrVerificationFailed {
  os.Exit(1)
}

Decrypting

key, _ := ioutil.ReadFile("saml.key")
doc, _ := ioutil.ReadAll(os.Stdin)
plaintextDoc, err := Decrypt(key, doc)
os.Stdout.Write(plaintextDoc)

Encrypting

key, _ := ioutil.ReadFile("saml.crt")
doc, _ := ioutil.ReadAll(os.Stdin)
encryptedDoc, err := Encrypt(key, doc, EncryptOptions{})
os.Stdout.Write(encryptedDoc)

Install

This package uses cgo to wrap libxmlsec. As such, you'll need libxmlsec headers and a C compiler to make it work. On linux, this might look like:

$ apt-get install libxml2-dev libxmlsec1-dev pkg-config
$ go get github.com/crewjam/go-xmlsec

On Mac with homebrew, this might look like:

$ brew install libxmlsec1 libxml2 pkg-config
$ go get github.com/crewjam/go-xmlsec

Static Linking

It may annoy you to grow a depenency on the shared libraries for libxmlsec, libxml2, etc. After some fighting, here is what I made work on Linux to get a static binary. See also Dockerfile.build-static which build the example program using this method.

Compile libxml

curl -sL ftp://xmlsoft.org/libxml2/libxml2-2.9.4.tar.gz | tar -xzf -
cd /libxml2-2.9.4
./configure --enable-static --disable-shared --without-gnu-ld --with-c14n --without-catalog --without-debug --without-docbook  --without-fexceptions  --without-ftp --without-history --without-html --without-http --without-iconv --without-icu --without-iso8859x --without-legacy --without-mem-debug --without-minimum --with-output --without-pattern --with-push --without-python --without-reader --without-readline --without-regexps --without-run-debug --with-sax1 --without-schemas --without-schematron --without-threads --without-thread-alloc --with-tree --without-valid --without-writer --without-xinclude --without-xpath --with-xptr --without-modules --without-zlib --without-lzma --without-coverage
make install

Compile openssl

curl -sL ftp://ftp.openssl.org/source/openssl-1.0.2h.tar.gz | tar -xzf -
cd openssl-1.0.2h
./config no-shared no-weak-ssl-ciphers no-ssl2 no-ssl3 no-comp no-idea no-dtls no-hw no-threads no-dso
make install

Compile libxmlsec

curl -sL http://www.aleksey.com/xmlsec/download/xmlsec1-1.2.22.tar.gz | tar -xzf -
./configure --enable-static --disable-shared --disable-crypto-dl --disable-apps-crypto-dl --enable-static-linking --without-gnu-ld       --with-default-crypto=openssl --with-openssl=/usr/local/ssl --with-libxml=/usr/local --without-nss --without-nspr --without-gcrypt --without-gnutls --without-libxslt
make -C src install
make -C include install
make install-pkgconfigDATA

Build with static tag

go build -tags static -ldflags '-s -extldflags "-static"' -o /bin/xmldsig-static.bin ./examples/xmldsig.go

Running ldd on the output should produce not a dynamic executable.